Intellectual creations appearing in patents reflect the basic values that represent criteria for economic competitiveness and development level of a country. The knowledge recorded in patent documents is fundamental to avoid parallel research and reinventions leading to wasted intellectual and material resources. Electronic information tools have reduced the time for legal right examination needed before starting new development and manufacturing projects. The free services of the Patent Library of the Hungarian Patents Office have made available patent descriptions by the use of international and domestic CD-ROM databases described by the authors: IPC:CLASS, Patent Bible, HUNPATÉKA, GLOBALPat, ESPACE BULLETIN, ESPACE-ACCES, USPS, PAJ,.